In recent years, electroluminescent (E.L.) lamps have gained popularity as a relatively inexpensive and attractive advertising display. E.L. lamps typically include an insulative material, electroluminescent materials, shielding material, and an electrically conductive material deposited in multiple layers to form an integral lamp. Such a lamp is illustrated in U.S. Pats. No. 4,617,195; 4,626,742; and 4,752,717. E.L. lamps require an AC voltage of typically 120 volts at an increased frequency, typically between 300 Hz and 3000 Hz. Further, E.L. lamps have shortened lives as voltage or current increase.
Currently, E.L. lamps are powered by a power supply generating a quasi-sine wave-AC signal at the increased frequency. Such supplies typically do not yield a true or pure AC voltage and, therefore, the life of the lamp is shortened. Further, the E.L. lamps are capacitive in nature. Current power supplies are "matched" only to the capacitive value of the lamp when new or at an average capacitive value. Matching the capacitive load (E.L. lamp) to the load is highly desired to increase efficiency of the power supply and reduce overheating problems. Through use the capacitive value of the E.L. lamp changes. Therefore, as the lamp ages and its capacitance changes the lamp and power supply become "unmatched" which decreases the efficiency of the power supply. Further an unmatched relationship between the power supply and the lamp causes the lamp to illuminate less.
Finally, current Dower supplies for E.L. lamps can either be turned on or off. When the power supply is turned on, a constant AC voltage is supplied to the lamp whether or not there is anyone in the vicinity of the lamp to view it. This also minimizes the useful life of the lamp whose purpose is to act as an attractant. Current power supplies also do not have the capability to illuminate separate segments of a multi-segment E.L. lamp.